A vast majority of Destiny's PvP maps are very suitable to CQCB which is why scout rifles are not used that often. Only in maps like First Light Bastion and Skyshock are scout rifles really a valuable primary to have equipped. Scout Rifles also require skill to use which the vast majority of Destiny players don't have seeing as all they can do is use Thorn. With a Scout Rifle, you must consecutively land 3-4 maybe 5 hits in the head in a row while under pressure and possibly having to deal with flinching from enemy fire. Truth is, I doubt many players out there are capable of this. Now to those who are going to say "I bet I can do that" then do it. Equip a VOC or Scholar or what have you and see if you can maintain your current average K/D while still playing the way you currently do. The maps do not provide any advantages to Scout Rifles with there TTK times being much higher than many other popular weapons and the poor performance at close ranges.